Rotatable flange adapter

ABSTRACT

Rotatable flange adaptor or rotatable flange is provided, such that bolt holes may be aligned for joining of flanges. A sealing device may be added to the hub of the adaptor, such that the sealing surfaces are not rotated. Keys are placed in races to provide for transmittal of force along the axis of the device while allowing rotary motion of a flange or flange adaptor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Apparatus for providing a rotatable pipe flange is provided. More particularly, a rotatable flange adapter or rotatable flange is provided that may be used, for example, on land drilling rigs between a blowout preventer and a flanged connector and for other applications.

2. Description of Related Art

Normal practice in drilling of wells for hydrocarbon production is to place a blowout preventer (BOP) at the surface of the earth. This is a device designed to prevent flow outside the drill pipe should excess pressure be encountered during drilling of a well. When drilling a well that may encounter high pressure, a ram-type BOP is employed, along with an annular BOP and related equipment to form a “BOP stack.” The combined devices may weigh as much as 85,000 pounds or more. The rams may extend several feet in a vertical plane in each direction from the axis of the BOP.

During drilling of wells, the BOP stack is connected to casing that has been previously placed in the well. The BOP stack may be installed and removed several times during drilling of the well as additional casing strings are placed and cemented in the well. The first casing string placed in the well is called the “conductor casing.” It may be driven into the earth or placed and cemented in a drilled hole. Conductor casing is often 20 inches in outside diameter. After it is placed, the well is drilled to a selected depth and the next smaller casing string is placed in the well. In land wells, this is often a casing string having a diameter of 13- 5/8 inches. It is called the “surface casing.” FIG. 1 illustrates well 10 that has been drilled to an intermediate depth. Conductor casing 11 was placed in the well at a shallower depth, then the well was drilled deeper and surface casing 12 was placed in the well and cemented in place. Casing head 14 was attached to the top of surface casing 12. Spool 16 has been placed on the surface casing. Spool 16 may be a tubing head spool, for example, or may be a spool for supporting a smaller casing string. Spool 16 has flange 18, which may have a diameter of 11 inches or 13- 5/8 inches. Casing head 14 of surface casing 12 normally has a 13- 5/8-inch flange. Double studded adaptor 20 is necessary to join casing head 14 and spool flange 18 if flange 18 is 11-inch. Typical wellhead assembly nomenclature and geometry are provided in API Specification 6A/ISO 10423, available from the American Petroleum Institute.

A conventional BOP flange, having a diameter of 13- 5/8 inch, is suited for use on the surface casing head, which normally has a 13- 5/8-inch flange. However, after the first spool is attached, as shown in FIG. 1, when the blow-out preventer is to be re-attached for drilling ahead, another spool adapter must be used to transition from flange 19, which is an 11-inch flange, to a 13- 5/8-inch flange. This can be accomplished by use of double studded adapter 20, placed in the reverse direction from its initial use between flange 14 and flange 18.

To understand the need on a drilling rig for the invention disclosed here, the procedure for attaching a BOP stack to flange 19 or flange adaptor 20 must be understood. Referring to FIG. 2, BOP stack 22, which may be comprised of BOP pipe rams 22A, annular preventer 22B and other ram 22C, is supported from beams 23 under the drilling floor (not shown) of a land rig by supports 23A and hoist 23B. It is common practice now for the workers to rotate BOP stack 22 while it is hanging from beams 23 by applying force to hoists 23B. This may be necessary in order: to align bolt holes in flanges 24 and 19 or a double-studded adaptor attached to flange 19, or to avoid interference of a structure under the rig floor with rams 22A, for example. This rotation places unpredicted side loads on BOP stack 22 and unpredicted additional tension in supports 23A. The rotation also causes BOP stack 22 to move upward, requiring adjusting hoist 23B to lower stack 22. This rotation and lowering of the BOP to match flanges becomes an operation that can put workers at risk. Hence, the need for the rotatable flange adapter 25, disclosed herein. Alternatively, a rotatable flange could be provided as an integral part of a BOP stack.

Other instances arise where rotatable pipe flange adaptors or rotatable flanges are needed. The need may arise when flanges are used for structural applications. In this instance there is no requirement for a pressure seal between flanges, and the flanges then are used to transfer mechanical forces. A rotatable flange can provide adjustable positions of structural parts. When pressure is to be confined in tubulars attached to the flanges, a seal is required, but rotatable flanges may still be needed to allow infinite adjustment of the angle of one flange with respect to another flange. A rotatable flange will not be limited to aligning flanges only by rotating to another bolt hole in the flanges.

A swivel ring flange is known in the art. Such devices are available from the HydroTech division of Oil States, for example. This device, although it facilitates bolt hole alignment, requires external retaining means for keeping a rotating flange ring integral to the hub of the device. “Rotating Joint” devices are also known and available from FMC and others. Typical rotating joints are designed to allow for one segment of a pressure-containing pipe to rotate relative to another segment. The joint also includes a pressure seal between the rotating segments.

What is needed is apparatus and method that eliminate the need to rotate a BOP stack in order to match bolt holes in flanges or to avoid interference from rig structure with a BOP. Also, apparatus and method are needed to provide adjustment of the angular position of one flange with respect to another flange and transmitting force between the flanges, with or without pressure sealing between the flanges.

SUMMARY OF INVENTION

In one embodiment, rotatable flange adaptor is provided that can be used to align a blowout preventer (BOP) flange and a flange on a well structure without rotating the BOP during installation. This is accomplished by providing a device comprised of two parts, called a hub and a ring, that are rotatable around their common axis. The hub and the ring each have a flange of a selected size and hole-pattern. The hub provides a pressure seal inside the contact between the hub and ring, so no moving pressure seal is necessary. The hub and ring are joined mechanically by keys inserted in matching races in each of the moving parts. In an alternate embodiment, the hub is made an integral part of a blowout preventer or other apparatus and a rotatable flange is mechanically joined thereto. In yet another embodiment, rotatable flange or flange adaptor without a pressure seal is provided for structural applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates common industry practice during drilling of a well, where two casing strings and a spool have been installed by using a double-studded adaptor (Prior Art).

FIG. 2 illustrates installation of a BOP stack on a spool using a rotatable flange adaptor disclosed herein.

FIG. 3 is a drawing of one embodiment of a rotatable flange adaptor wherein the hub and ring are mechanically joined by cylinders in races formed in each part.

FIG. 4 is a cross-sectional view of the rotatable flange adaptor of FIG. 3.

FIG. 5 is a drawing of one embodiment of a rotatable flange adaptor wherein the hub and ring are mechanically joined by balls in races formed in each part.

FIG. 6 is a cutaway view of the rotatable flange adaptor of FIG. 5.

FIG. 7 is a drawing of one embodiment of a rotatable flange adaptor wherein the hub and ring are mechanically joined by a split ring in races formed in each part.

FIG. 8 is an assembly view of the rotatable flange adaptor of FIG. 7.

FIG. 9 is a drawing of a rotatable flange as an integral part of a blowout preventer.

FIG. 10 is a close-up view of the rotatable flange of FIG. 9.

FIG. 11 is a side view of the rotatable flange and blowout preventer of FIG. 9.

DETAILED DESCRIPTION

Referring to FIG. 1, well 10 is being drilled in the earth. Conductor casing 11 has been placed in the well and the well has then been drilled below the conductor casing to a selected depth. Surface casing 12 has then been placed in the well and cemented in place. Casing head 14 has been attached to surface casing 12 and double studded adapter 20 has been attached to the casing head. Spool 16, having flanges 18 and 19, has been attached to the double studded adapter. The double studded adapter is necessary when flange 18 on spool 16 is smaller in size then the flange on casing head 14. With this equipment on the well, the well is to be drilled deeper toward a target in the earth. Before drilling proceeds below surface casing 12, it is necessary to attach a blowout preventer (BOP) to the casing in the well.

Referring to FIG. 2, blowout preventer stack 22 is to be attached to the well. Stack 22 is supported from beams 23 below the drilling rig floor. Supports 23A and hoist 23B support stack 23. Stack 22 includes annular BOP 22B and ram-type BOPs 22A and 22C. The BOP stack may also include other equipment not shown in FIG. 2. At the bottom of stack 22 is flange 24, which is to be attached to the well by flange 19 and pressure-sealed. Normally, flange 19 has a diameter of 11 inches. Therefore adapter 25 must be inserted between the 11-inch flange 19 and the normally 13- 5/8-inch flange 24 on a BOP. One alternative is to employ a double studded adapter, such as shown at 20 in FIG. 1, in the opposite direction to convert the 11-inch connection to a connection suitable for the 13- 5/8-inch flange 24. This is normal practice. Flange 25 of FIG. 2 is the rotatable flange disclosed herein. It will be described in more detail, in its various embodiments, below. A salient feature of adapter 25 is that it provides a means to avoid rotating BOP stack 22 while it is being placed on the well using supports 23A and hoists 23B.

FIG. 3 shows a drawing of one embodiment of a rotatable flange adapter. Hub 30 includes race 32A. At the top of hub 30 is ring groove 35, adapted to receive ring gaskets (not shown), which provide a pressure seal on hub 30. Other means for providing a pressure seal may be provided, such as an o-ring in an o-ring groove, or other sealing methods known in the art may be used. A ring groove or other sealing means is also present on the other (not shown) side of hub 30. Ring 38 is adapted to be placed over hub 30 and to rotate with respect to hub 30 above a shoulder on the hub. Ring 38 includes boltholes 39, port 40 and race 32B. Port 40 is to be used for placing cylinders 34 into the space between races 32A and 32B. After cylinders are placed, using procedures described below, plug retainer 42 is inserted into port 40 and held in place by screw 42A. A port for grease injection into race 32B (not shown) may be placed in ring 38. Grease seals may be added on each side of the race in either ring 38 or hub 30.

To assemble the adapter flange, hub 30 may be placed on a bench and supported with its axis in the horizontal direction. Ring 38 may then be lifted with an overhead hoist and its internal diameter placed over hub 30 in a concentric location. Port 40 would preferably be in a vertical or 12 o'clock position. Rollers would then be inserted through port 40 and allowed to find the bottom of races 32A and 32B, which are preferably filled with cylinders. Once all of the cylinders are placed, plug 42 is inserted and fastened into place with screw 42A.

FIG. 4 shows a cross-sectional view of the flange adapter of FIG. 3. Ring 38 is adapted to rotate on hub 30, with cylinders 34 in matching races that are formed into hub 30 and ring 38. Cylinders 34 serve as shear keys. They are used to transmit forces from the hub to the ring. Port 42 is sized to allow cylinders 34 to pass down the port, into the races without becoming lodged in the port. Ring groove 35 at the top of hub 30 and ring groove 33 at the bottom of hub 30 are also shown. Holes 31 are preferably threaded and sized to accept stub bolts used for attaching hub 30 to other pressurized equipment. Holes 37 are provided to be used by insertion of a rod or other tool in a hole to assist in rotating ring 38. Alternatively, flats may be formed on ring 38 to assist in rotating ring 38.

FIG. 5 illustrates an alternate embodiment of a rotatable adapter flange. Hub 50 includes race 52A, which receives balls 54. Matching race 52B has been formed in ring 58. Ring 58 also includes bolt holes 59 and holes 60 for assisting in rotation of the ring. Grease port and seals (not shown) may be added for supplying grease to the races.

FIG. 6 shows a cutaway view of the rotatable adapter flange of FIG. 5. Hub 50 includes bolt holes 51 that are threaded to receive stud bolts. Ring groove 63 is adapted with ring gaskets (not shown) for pressure sealing of hub 50 to adjoining apparatus. Port 61 allows placement of balls 54 into the races between hub 50 and ring 58. Plug 62 may be placed into port 61 after balls 54 are in place. Again, balls 54 serve as shear keys to couple hub 50 and ring 58 so that forces may be transmitted between of the two parts of the rotatable adapter flange.

Referring to FIG. 7, yet another alternative embodiment of a rotatable adapter flange is illustrated. Hub 70 contains race 72A and seal ring groove 76. Ring 78 is sized to be placed on hub 70, with matching race 72B. Split ring 74 is placed in race 72B before ring 78 is brought into place over hub 70. Ring 78 is then placed over hub 70. Fasteners 82 are then inserted into holes 80 to cause split ring 74 to move into a keying position in matching races 72A and 72B. The location of fasteners 82 may be measured and marked such that split ring 74 is in proper position. Bolt holes 79 may be used for mating ring 78 with adjoining equipment. Provisions for supplying grease to the races may be added, as described above.

FIG. 8 shows a drawing of the rotatable adapter of FIG. 7 after ring 78 is in place and stud bolts 82 have been inserted and moved to position to place the split ring in a keying position between hub 70 and ring 78.

The rotatable flange adapters illustrated in the figures above are provided as separate apparatus that may be attached to well equipment such as shown in FIG. 2. The equipment may be installed at a well site as follows. The hub (13- 5/8 inch side) is bolted to the bottom flange of the BOP using stud bolts. The BOP is moved into position over the wellhead mating flange, as shown in FIG. 2. This flange is normally an 11-inch flange. The ring portion of the adapter flange may then be rotated to mate stud bolts 25A in the holes of flange 19. The blind drilled holes such as shown at 60 in FIG. 5 or in FIG. 7 may be used along with a spanner or cheater bar to assist in rotating a ring to the desired position. A flange gasket may be put into place in a groove. Illustrated in the figures is a ring gasket; however it should be understand that any other flange-sealing apparatus may be used. The BOP may then be lowered down to rest on the mating gasketed flange. Stud bolts may then be installed and tightened as required.

Referring to FIG. 9, a rotatable flange on an integral hub is illustrated. BOP rams 90 have integrally formed hub 92. Race 94A has been formed in hub 92. Ring 98, having matching race 94B, is adapted to be placed over hub 92. Shear keys such as cylinders 96 may then be placed in races 94A and 94B. Plug 99 is sized to be used in port 99A

By using an integral hub to a BOP, as shown in FIG. 9, a manufacturer may avoid welding a ring flange hub to the BOP body. Welding requires a high-integrity connection, which is very costly. This is especially true for high pressure ratings, where thick walls are necessary. Therefore, the manufacturers of these components either cast of forge the basic shape of the flange into the body of the pressure-containing parts. Prior art ring flanges must be welded on since the outer ring is assembled onto the hub from one side to mate the load-bearing shoulders. This limits assembly to the side that is to be welded onto the component fitted to. In the apparatus disclosed herein, the ring can be assembled to the hub without the limitation posed by the load shoulder.

FIG. 10 shows a close-up of the flange of FIG. 9. Port 99A is more clearly seen, along with cylinders 96 that may be inserted through port 99A. FIG. 11 is a side view of the same apparatus, showing that hub 92 is make integral with BOP 90.

Although the present disclosure has been described in detail, it should be understood that various changes, substitutions and alterations can be made thereto without departing from the scope and spirit of the invention as defined by the appended claims. 

1. A rotatable flange adaptor having an axis, comprising: a hub, the hub having an upper face, a lower face having bolt holes, and a first convex race between the upper face and the lower face; a ring adapted to rotate on the hub, the ring having bolt holes, and a second concave race matched to the first race; and at least one key, the key being adapted to fit in the first convex race and the second concave race so as to transmit force between the hub and the ring.
 2. The rotatable flange adaptor of claim 1 further comprising a first pressure-sealing device on the upper face and a second pressure-sealing device on the lower face.
 3. The rotatable flange adaptor of claim 1 wherein the ring further comprises a port and the key is comprised of a cylinder.
 4. The rotatable flange adaptor of claim 1 wherein the ring further comprises a port and the key is comprised of a ball.
 5. The rotatable flange adaptor of claim 1 wherein the ring further comprises adjustable screws and the key is comprised of a split ring.
 6. The rotatable flange adaptor of claim 2 wherein at least one of the first pressure-sealing device or the second pressure-sealing device is comprised of a ring groove and ring gasket.
 7. The rotatable flange adaptor of claim 1 wherein the ring further comprises holes adapted to receive a device for turning the ring.
 8. A blowout preventer having a rotatable flange connector, comprising: a blowout preventer having a bore therethrough; a hub pressure-connected to the bore, the hub having an axis, a lower face having a pressure-sealing device and a first convex race between the blowout preventer and the lower face; a ring adapted to rotate on the hub, the ring having bolt holes and a second concave race matched to the first race; and a key, the key being adapted to fit in the first convex race and the second concave race so as to transmit force between the hub and the ring along the axis of the hub.
 9. The rotatable flange connector of claim 8 wherein the ring further comprises a port and the key is comprised of a cylinder.
 10. The rotatable flange connector of claim 8 wherein the ring further comprises a port and the key is comprised of a ball.
 11. The rotatable flange connector of claim 8 wherein the ring further comprises adjustable screws and the key is comprised of a split ring.
 12. The rotatable flange connector of claim 8 wherein at least one of the first pressure-sealing device or the second pressure-sealing device is comprised of a ring groove and ring gasket.
 13. The rotatable flange adaptor of claim 8 wherein bolt holes of the hub are adapted to match the bolt holes of an 11-inch flange.
 14. The rotatable flange adaptor of claim 8 wherein the ring further comprises holes adapted to receive a device for turning the ring.
 15. A method for placing a blowout preventer on a well, comprising: providing the rotatable flange adaptor of claim 2; bolting the hub side of the adaptor to the bottom flange of a BOP with the first sealing device in place; moving the BOP over the wellhead mating flange; rotating the ring of the adapter flange to mate the bolt holes or align the BOP in a preferred direction; and placing the second sealing device, lowering the BOP and installing bolts. 